UFG is an stakeholder company shared 50-50 between Naturgy Energy Group, S.A. and Eni SpA
UFG originated in February 1998 as a gas subsidiary of the electricity utility Unión Fenosa. In 2003, the Italian company Eni SpA entered as a strategic partner of UFG, acquiring 50% of the shares and strengthened the company's positioning in the international gas markets.
In April 2008, after approval from their respective boards of directors, the proposed merger of Gas Natural and Unión Fenosa and Unión Fenosa Generación was approved. Full integration of Unión Fenosa into Gas Natural took place on 4 September 2009. Thus, Gas Natural (now Naturgy) became a 50% shareholder in UFG together with Eni.
UFG operates independently as one of the most important companies in the gas sector in Spain with the strength of those two relevant shareholders.